Hydrotreating process for heavy hydrocarbon oils

摘要

An improvement in a process which comprises feeding a heavy hydrocarbon oil and hydrogen to a fixed bed reactor which is charged with a demetallation catalyst at its upper stage and a hydrotreating catalyst at its lower stage, first contacting said feed stock with the demetallation catalyst under hydrotreating conditions and then contacting the same with the hydrotreating catalyst for the purpose of hydrotreating. The improvement comprises providing at the upper stage of the demetallation catalyst bed a small volume of a premetallation catalyst bed, said premetallation catalyst being lower in the activity than the demetallation catalyst. This predemetallation catalyst bed is charged with a catalyst which comprises one kind or more of metals selected from Group IIB, Group IVB, Group VB, Group VIB and Group VIII supported on a porous inorganic oxide carrier, said metals being 0.2 to 3 wt. % in terms of oxide, and has a pore volume of 0.4 to 1.5 ml/g and a void fraction of 55 vol % or more.